Anniversary clocks can provide many years of trouble free service with no maintenance. Because these clocks run so slowly, wear to components is minimal compared to other mechanical clocks. The dome or case also helps to protect the movement from dust. Even so, old oil eventually dries out and becomes sticky, and dust particles accumulate over time. Acting together, friction is increased until it reaches a point where the clock will no longer run. You may be able to extend the interval between servicing without causing damage by periodically applying a very small amount of clock oil with a small artist’s brush or pen oiler to the gears’ pivots (the thin ends of the gears) where they extend through their bushings (holes in the plates), on both the back plate and front plate, and a tiny dab between the ratchet wheel and plate, and nowhere else. You just want to barely wet the pivots. Do not use any other type of oil, and never spray the movement with WD40. Oiling a dirty movement and then running the clock may accelerate wear to pivots and bushings.